Modified natural kaolin clay as an active, selective, and stable catalyst for methanol dehydration to dimethyl ether

In this work, the production of dimethyl ether (DME) from methanol over natural kaolin clay modified through impregnation with various percentages of H₂SO₄, WO₃, or ZrO₂ catalysts was investigated. The prepared catalysts were characterized via X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and N₂-sorption analysis. The acidity of these catalysts was determined through the dehydration of isopropyl alcohol and the chemisorption of pyridine. The catalytic activity performance revealed that the addition of modifiers into kaolin enhanced the latter’s activity toward DME production. In addition, the kaolin clay modified with 10 wt% ZrO₂ exhibited excellent activity of 98% conversion with 100% selectivity at 275 °C. Moreover, this catalyst could proceed the reaction for a long time (6 days) without any noticeable deactivation. The remarkable improvement in the catalytic performance achievement was well correlated with the acidity and the structure of the catalysts.

Analysis of Liquid Organic Hydrogen Carrier Systems

Liquid organic hydrogen carriers (LOHCs) provide attractive opportunities for hydrogen storage and transportation. In this study, a detailed examination of the most prominent LOHCs is performed, with a focus on their properties and scope for successful process implementation, as well as catalytic materials used for the hydrogenation and dehydrogenation steps. Different properties of each potential LOHC offer significant flexibility within the technology, allowing bespoke hydrogen storage and transportation solutions to be provided. Among different LOHC systems, dibenzyltoluene/perhydro-dibenzyltoluene has been identified as one of the most promising candidates for future deployment in commercial LOHC-based hydrogen storage and transport settings, based on its physical and toxicological properties, process conditions requirements, availability and its moderate cost. PGM-based catalysts have been proven to catalyse both the hydrogenation and dehydrogenation steps for various LOHC systems, though base metal catalysts might have a potential for the technology.